The invention relates generally to the field of surgical instruments and is more particularly directed to a hand-held surgical instrument used for forming radially oriented incisions particularly suited for surgery to correct the effects of myopia or astigmatism.
It has been determined that myopia (or nearsightedness) and astigmatism are directly related to the curvature of the eye, and in particular of the cornea. Varying the degree of curvature of the cornea will, therefore, directly affect the degree of myopia and astigmatism. Recently, surgical techniques have been developed to vary the degree of curvature of the cornea. These techniques involve the placement of radial incisions, varying in length, about the cornea and extending up to or into the sclera. Further descriptions of this surgical technique can be found in articles by Professor S. Fyodrov; William D. Myers, M.D.; Leo Bores, M.D.: Ronald A. Schacher, M.D., et al; Ronald A. Schacher, M.D. alone; and Ronald A. Schacher, M.D. with Les Schacher, M.D.; all published in the Proceedings of the Keratorefractive Society for the meeting dated June 21, 1980.
Heretofore, the placement of the radially arranged incisions has been accomplished by free hand. Placement and positioning of the incisions has thus far, been the result of the surgeons eye judgement. The success or failure of the technique to vary the curvature of the cornea will depend to a great degree on the proper spacing of the radial incisions. It is desirable that the incisions be equi-distantly spaced to enhance the control of the procedure.
It has also been found that the depth of the incisions is a critical factor in determining the degree of varying the curvature of the cornea.
The length of the incisions, the remaining optical zone and the angle of the incisions with respect to the surface of the cornea are also critical factors in performing a successful procedure. It has been found desirable that the angle of the incisions be 90.degree. (i.e. perpendicular) with respect to the surface of the cornea. Incisions which are not perfectly radial will also have an adverse effect on the results of such an operation.
Because the radial incisions have heretofore been typically formed by free hand, no two operations can ever be expected to be exactly the same. Further, control over the critical factors (i.e. spacing, length, depth and perpendicularity) are difficult, if not impossible, to control when forming the incisions by free hand. The results to be expected from such surgical procedures cannot, therefore, be predicted when using a free hand technique.
It is, accordingly, a general object of the present invention to provide an ophthalmological surgical instrument, useful for forming perfect radial incisions about the cornea which overcomes the disadvantages of using a free hand technique.
It is a more specific object of the present invention to provide such a surgical instrument which enables the surgeon to accurately space the radial incisions equi-distantly for uniformity and predictable results.
It is yet a further object of the present invention to provide a device for forming radial incisions in the cornea of the eye which has means for adjusting and controlling both the spacing of the radial incisions and the depth of the incision.
Another object of the invention is to provide a radial keratotomy device having means to control the length of the radial incisions and therefore, the size of the optical zone.
Still a further object of this invention is to provide a device for forming radial incisions in the cornea which are perpendicular to the surface of the cornea.
The above objects, features and advantages, along with other objects, features and advantages of the present invention will become more apparent from the detailed description of the invention in conjunction with the accompanying drawings to be described more fully hereinafter.